1. Field of the Invention
The present invention relates to a heat exchanger which is manufactured by unit brazing.
2. Related Art
For manufacturing a heat exchanger such as a refrigerant evaporator, a refrigerant condenser, a radiator used in a refrigeration cycle by unit brazing, each part is assembled in a certain position (core assembling), and such assembled state should be kept until the brazing has been completed to prevent the parts from dropping off and slipping.
So, in a conventional manufacturing method, the parts which have been assembled are temporarily fixed, for example, the parts are crimped or partially connected together by welding or brazing. The temporary fixation of the parts holds the assembled state of the parts temporarily until the unit-brazing is completed, however, it may require more time and expense than needed.
For example, in the temporary fixation by crimping, a process for deforming a portion of the part and forming a crimped portion is needed. In the temporary fixation by welding, the parts should be heated and a process for supplying welding material is needed. In the temporary fixation by brazing, a process for supplying brazing material is needed. As a conventional pipe connecting structure, two pipes are connected by locking a pin in a keyhole or driving one pipe along a cam face formed on the other pipe (e.g., Japanese Utility Model Applications Laid-Open Nos. 5-45385, 1-150294, etc.).
However, when at least one of two pipes is covered with a clad material for brazing and is heated, such locking may be loosened because the clad material is molten by heating thereby causing a gap in the locking portion. So, it is difficult to perform the brazing and maintain the parts accurately positioned.